Biopsy device arming mechanism
A biopsy device for percutaneous tissue removal includes an elongated housing having an operational axis, a stylet hub slidably mounted in the housing, where the stylet hub is movable relative to the housing between a proximal, armed position, and a distal, fired position, the stylet hub having a stylet strike, a cannula hub slidably mounted in the housing alongside the stylet hub, and a spring-biased arming member. The cannula hub is movable relative to the housing between a proximal, armed position, and a distal, fired position. The arming member is moveably mounted to the housing proximal of the respective stylet and cannula hubs, and configured for manually-actuated movement from a relaxed, extended position to a loaded, compressed position to define a compressive arming stroke. The biopsy device also includes an arming member biasing spring that restores the arming member from the compressed position to the extended position.
1. A hand-held biopsy device, comprising:
an elongated housing having an operational axis extending between a proximal portion of the housing and a distal portion of the housing, the distal portion of the housing comprising a first deflectable wall portion and a second deflectable wall portion, each of the first deflectable wall portion and the second deflectable wall portion being integrally formed with the distal portion of the housing to form an exterior surface of the biopsy device;
a stylet hub slidably mounted in the distal portion of the housing, the stylet hub being movable relative to the housing, along the operational axis, between a stylet hub proximal, armed position and a stylet hub distal, fired position;
a cannula hub slidably mounted in the distal portion of the housing alongside the stylet hub, the cannula hub being moveable relative to the housing, along the operational axis, between a cannula hub proximal, armed position and a cannula hub distal, fired position;
a first control button coupled to the first deflectable wall portion; and
a second control button coupled to the second deflectable wall portion, the second control button overlapping at least a portion of the first deflectable wall portion and at least a portion of the second deflectable wall portion,
wherein, when the stylet hub is in the proximal, armed position, deflection of the first deflectable wall portion propels the stylet hub to the stylet hub distal, fired position, and
wherein, when the cannula hub is in the proximal, armed position, deflection of the second deflectable wall portion propels the cannula hub to the cannula hub distal, fired position.
2. The biopsy device of claim 1 , further comprising:
a stylet having a proximal end portion coupled to the stylet hub and a tissue piercing distal portion extending beyond a distal end of the housing;
a stylet hub biasing spring configured to drive the stylet in a distal direction relative to the housing; and
a stylet hub catch configured to releasably retain the stylet hub biasing spring in a compressed state and the stylet hub in the stylet hub proximal, armed position.
3. The biopsy device of claim 2 , further comprising:
a cannula having a proximal end portion coupled to the cannula hub, the cannula being disposed coaxially around the stylet and having an open-end distal portion extending beyond the distal end of the housing;
a cannula hub biasing spring configured to drive the cannula over the stylet in the distal direction relative to the housing; and
a cannula hub catch configured to releasably retain the cannula hub biasing spring in a compressed state and the cannula hub in the cannula hub proximal, armed position.
4. The biopsy device of claim 3 , wherein:
when the stylet hub is in the proximal, armed position, deflection of the first deflectable wall portion releases the stylet hub catch to release the stylet hub biasing spring and propel the stylet hub to the stylet hub distal, fired position, and
when the cannula hub is in the proximal, armed position, deflection of the second deflectable wall portion releases the cannula hub catch to release the cannula hub biasing spring and propel the cannula hub to the cannula hub distal, fired position.
5. The biopsy device of claim 4 , wherein the first deflectable wall portion is separated from the second deflectable wall portion such that the deflection of the first deflectable wall portion does not release the cannula hub catch and the deflection of the second deflectable wall portion does not release the stylet hub catch.
6. The biopsy device of claim 4 , wherein, when the stylet hub and the cannula hub are respectively in the stylet hub proximal, armed position and the cannula hub proximal, armed position, depression of the second control button sequentially deflects the first and second deflectable wall portions, to sequentially release the stylet hub catch and the cannula hub catch to sequentially drive the respective stylet and cannula in the distal direction relative to the housing.
7. The biopsy device of claim 1 , wherein, when the second control button is depressed, the second control button is configured to sequentially deflect the first deflectable wall portion and then the second deflectable wall portion.
8. The biopsy device of claim 1 , wherein overlapping portions of the second control button and the first deflectable wall portion are separated by a first distance and overlapping portions of the second control button and the second deflectable wall portion are separated by a second distance, the second distance being greater than the first distance.
9. The biopsy device of claim 8 , wherein, the second distance between the overlapping portions of the second control button and the second deflectable wall portion creates a gap between the second control button and the second deflectable wall portion, such that, when the second control button is depressed, the second control button passes through the gap before making direct contact with the second deflectable wall portion to deflect the second deflectable wall portion.
10. The biopsy device of claim 1 , further comprising a spring-biased arming member moveably mounted to the proximal portion of the housing, the spring-biased arming member being configured to be manually actuated from a relaxed, extended position to a loaded, compressed position to define a compressive arming stroke, the compressive arming stroke being configured to move each of the stylet hub and the cannula hub into the respective stylet hub proximal, armed position and the cannula hub proximal, armed position.
11. The biopsy device of claim 10 , wherein the arming member is sized and configured to be manually actuated into the loaded, compressed position using one or more fingers of a single hand.
12. The biopsy device of claim 11 , wherein the proximal portion of the housing has a proximal end surface sized and configured for being retained against a palm of the single hand when the arming member is actuated.
13. The biopsy device of claim 10 , wherein, throughout a full range of movement of the arming member and a full range of movement of the cannula hub, a position of the arming member is proximal to a position of the cannula hub.
14. The biopsy device of claim 1 , wherein the first deflectable wall portion comprises a first lever and the second deflectable wall portion comprises a second lever, the first lever having a first free end the second lever having a second free end.
15. The biopsy device of claim 14 , wherein the first free end and the second free end abut one another along the operational axis.
16. The biopsy device of claim 15 , wherein the second control button overlaps at least a portion of each of the first free end and the second free end.